Patent Grant
11572994
The present invention relates to automobile lighting or signaling devices, and more particularly, to automotive lighting or signaling devices with associated light guide units.
Efforts to improve the lighting efficiency and homogeneity in vehicle lamps is an on-going endeavor among Original Equipment Manufacturers (OEM) and numerous component/system suppliers. Of particular interest is the desire to obtain the lighting appearance of an enhanced homogeneous lit area or a uniform light emitting area by using a single light source. The present invention is directed to one such innovation solution to provide optical device arrangements that can produce enhanced homogenous-lit areas by using a single light source.
In the field of automotive lighting and light signalling units, it is becoming increasingly common to use light sources based on light-emitting semiconductor components, for example, light-emitting diodes (LEDs). The light emitted by an LED may, in any known suitable manner, be coupled with a light guide. Light guides are used in exterior vehicle lighting applications and in a variety of other applications. The light beam emitted by LEDs generally enter a light guide via an entry face and leaves the light guide through an exit face. Between the entry face and the exit face, LED produced light rays are guided within the light guide by typically using reflective elements positioned inside the light guide. Light guides may be curved or rectilinear. Light guides can be oriented vertically or horizontally, as well.
When the light guide is of a curved shape, it presents a difficult challenge to achieve uniform lit appearance at the light exit face. Furthermore, when the light guide is oriented vertically, it often presents a difficult challenge to position light sources to face an optical axis of the light guide because of packaging limitations. To typically address such shortcomings, conventional light guide systems employ multiple light sources and multiple couplers to increase homogeneity and to enhance the light emitting area in order to meet road regulation lighting or signal function requirements. However, using multiple light sources and couplers for performing such optical functions continues to present and remains a space constraint challenge in the design of automotive vehicle lighting devices.
Among the literature that may pertain to this technology includes patent documents: U.S. Pat. No. 7,639,918 B2 and U.S. Pat. No. 7,686,497 B2; U.S. Publication US 2015 0233 539 A1, all incorporated herein by reference for all purposes.
Thus among various objectives that this invention addresses, an objective is to achieve optical efficiency and enhanced light-effect control over alternatives that use optical film or diffusive materials where lighting effects are achievable at the expense of less desirable appearances. Another objective is to allow enhanced control of lighting effects versus meeting regulatory luminance intensity requirements. And another objective is to leverage single light source-single or minimized-light coupler arrangements within constrained light-guide space systems to efficiently impact uniform light distribution appearances at a lit exit face. And yet another objective is to achieve luminance photometric values of ninety percent (90%) or within ten percent (10%) luminance variation consistently across a light-emitting face or lit exit face. The invention herein overcomes one or more of these known problems and shortcomings in the design and implementation of the automotive field's associated light guide devices.
The present invention is directed to a unique solution to one or more of the problems discussed above. It is believed that that the present invention provides a motor vehicle light-signal unit arrangement and light guide assembly having a curvilinear formed light guide, which can still produce the appearances of an enhanced homogeneous lit area or a light emitting area by efficiently using a single light source and a single coupler or light-coupling reflector.
Accordingly pursuant to a first aspect of the present invention, a vehicle light guide assembly is contemplated for lighting or signaling that comprises: a light guide comprising a light-emissive body, a light emitting face side, and a light reflecting face which is disposed opposite to the light emitting face or exit face side; a light source, wherein a light emission axis of the light source is substantially perpendicular to an optical axis of the light guide; a coupler positioned at the light source and configured to receive a light beam emitted from the light source, wherein the coupler is adapted to produce a collimated light beam from the light source; wherein the light reflecting face of the light guide is a stepped reflective surface formed by a plurality of light reflecting facets and a plurality of lateral surfaces that are alternatively arranged on the light reflecting face of the light guide; wherein the plurality of reflecting facets are optically functional and are angled at substantially 45 degrees to the light emission axis from the coupler, and the plurality of lateral surfaces are optically non-functional and parallel to the light emission axis; wherein the plurality of reflecting facets are configured to receive the collimated light beam and said plurality of reflecting facets direct the collimated light beam towards the light emitting face along the optical axis, and wherein a number of light reflective facets are configured to collect a collimated light beam portion at a middle portion of the light reflecting face in an amount that is less than a collimated light beam portion from a number of reflective surfaces from end portions of the light reflecting face; and wherein the middle portion of the light reflecting face receives the collimated light beam and has a luminous intensity value that is higher than a luminous intensity value received on the end portions of the light reflecting face by the collimated light beam.
The invention may be further characterized by one or any combination of the features described herein, such as: wherein a width of the light guide progressively decreases in a curved, tapering or transitional manner from a light receiving face of the light guide towards a face that is opposite to the light receiving face; the light emitting face side or exit face is provided with a plurality of exit facets, which are arranged at step-wise right angles or are angled substantially at 90 degrees with respect to the optical axis of the light guide; wherein the collimated light beam that is directed towards the exit face or light emitting face side is angled 90 degrees with respect to the collimated light beam that is received on the plurality of light reflecting facets; wherein the light guide produces a light beam that is homogenous or evenly distributed along the light guide's exit face or light emitting face side; wherein a width of the light distributed on the light emitting face side is more wide as compared to a width of the light beam's spread from the light source; wherein the light source is positioned on a Printed Circuit Board (PCB); wherein the light source is of a Light Emitting Diode (LED) type; wherein the light source and the coupler are positioned proximal to the light receiving face; and wherein the light reflecting face of the light guide body conforms to an S-shape.
Accordingly pursuant to a second aspect of the present invention, a motor vehicle lighting or signalling device is contemplated comprising: a reflector assembly; a lens; a housing; and a light guide assembly, wherein the light guide assembly comprises: a light guide comprising a light-emissive body, an exit face or light emitting face side and a light reflecting face that is disposed opposite to the light emitting face side; a light source, wherein a light emission axis of the light source is substantially perpendicular to an optical axis of the light guide; a light-coupling reflector or coupler is positioned at the light source and configured to receive a light beam emitted from the light source, wherein the coupler produces a collimated light beam from the light source; wherein the light reflecting face of the light guide is a stepped reflective surface arrangement formed by a plurality of light reflecting facets and a plurality of lateral surfaces that are alternatively arranged on the light reflecting face of the light guide; wherein the plurality of reflecting facets are optically functional and are angled at substantially 45 degrees to the light emission axis from the coupler, and the plurality of lateral surfaces are optically non-functional and parallel to the light emission axis; wherein the plurality of reflecting facets are configured to receive the collimated light beam and said plurality of reflecting facets direct the collimated light beam towards the light emitting face along the optical axis, and wherein a number of light reflective facets are configured to collect a collimated light beam portion at a middle portion of the light reflecting face in an amount that is less than a collimated light beam portion from a number of reflective surfaces from end portions of the light reflecting face; and wherein the middle portion of the light reflecting face receives the collimated light beam and has a luminous intensity value that is higher than a luminous intensity value received on the end portions of the light reflecting face by the collimated light beam.
It should be appreciated that the above referenced aspects and examples are non-limiting, as others exist within the present invention, as shown and described herein.
The present invention provides an automotive lighting and/or signalling device that can produce appearances of an enhanced homogeneous lit area or a light emitting area by efficiently using a single light source and a single coupler or single light-coupling reflector.
Of particular interest and the main focus of the present disclosure is to provide a lighting system arrangement or a light guide assembly as shown in
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this technology belongs.
It is contemplated that the relationships (e.g. at least the geometric properties and the material properties) between associated components and component assemblies are surprisingly important in solving one or more issues described in the background section above. Each of the components and component assemblies and their relationships are disclosed in greater detail and specifically in the following paragraphs.
Light Source 1
Light source represents a visually perceived source of electromagnetic radiation or an energized source of visually perceived radiant energy (inclusive of “Visible” light within the electromagnetic spectrum) but may include a broad combination or range of electromagnetic or radiant energy inclusive from among X-rays, ultraviolet and infrared energy, micro-wave and radio-wave spectrums. The light source may include every conventional and suitable lighting element sources such as filament-based or incandescent lamps, fluorescent lamps, arc or gas-discharge type lights, light emitting diodes (LED), or other suitable conventional sources.
The light source 1 preferably includes one or more Light Emitting Diodes (LEDs), however, other light sources may be used without falling outside the spirit and scope of the present invention. The light source is disposed at a predetermined point with respect to the light guide. The light source is positioned in such a way that light rays from the light source enter the light guide parallel to a longitudinal axis of the light guide. In an example, the light source is arranged on a printed circuit board (PCB) 133 (but not shown in the Figures). The PCB 133 is used to power, to control, and to carry the light sources. It will be noted that the light emission axis L from the light source 1 is perpendicular to an optical axis OA of the light guide 105. In an embodiment, the light source is positioned at a light receiving face 110 of the light guide 105 and in proximate to the light reflecting face 110.
Coupler 130
A coupler 130 or light-coupling reflector functions to gather surrounding generated light and distribute or redirect such associated generated light in a particular manner or tailored direction (a particular spot, location, randomized direction or a focused target area) using said coupler's reflective surface(s).
The coupler 130 is adapted to transmit the light from the source 1 towards the light guide 105. As shown in
Light Guide 105
The Light guide 105, which may be a refined component of Light-emissive medium 125, functions as the material body that a light wave (inclusive of electromagnetic particle or varying-spectrum light waves) passes through. For example, light waves traveling through or passing-through a guiding material or a “medium” material. Light guide 105 may be constructed or formed from a unitized, integral or from a combination of constituent body components. Light-emissive medium 125 material may include rigid bodies or a material body of varying flexibility or a material body of relative elasticity or a gel-rubberized material. Light-emissive medium 105 may be formed from a simple geometric or customized shape and may include various colorant or additive features which may interfere with light transmission at various levels yet still allow for light transmission through the “medium” body at various degrees.
The light guide 105 takes the form of a sheet. The term ‘sheet’ is understood to mean a shape bounded in the direction of the thickness by two faces that are substantially parallel to over another over at least a part of the shape. The shape of the sheet itself may have a non-planar shape. The light guide 105 has an elongated light-emissive body 125 constructed of light-transmitting material. According to an embodiment of the present invention, the light guide is preferably made of a transparent plastic, by means of injection molding. As shown in
Light guide 105 comprises the light receiving face 110, the light-emissive body 125, the light reflecting face 115, and the light emitting face side or exit face 120 disposed opposite to light reflecting face 110. Light receiving face 110 is adapted to receive light rays 145 from the light source 1. In an embodiment, the light guide 105 may conform to an S-shape. However, the present invention is not limited to S-shape light guides. Rather according to the present invention, the light guide 105 can be of any curved shape which could produce a uniform or homogenous lit appearance by using a single coupler and a single light source.
In an embodiment, a width of the light guide 105 may progressively decrease in a curved manner from the light guide's light receiving face 110 to a face that opposes light receiving face 110.
Light reflecting face 115 is formed on a side surface of the light-emissive body 125. The light reflecting face 115 of light guide assembly 100 includes a stepped reflective surface (depicted
Light reflecting facets 135 and lateral surfaces 140 may be alternatively arranged along the side surface of the light-emissive body 125 spanning the longitudinal axis L direction, as shown in
Furthermore, the plurality of lateral surfaces 140 are optically non-functional and parallel to light emission axis L, such that the lateral surfaces 140 typically do not reflect the light rays along Optical axis OA.
In an embodiment, the lengths of each reflecting facet 135 and the length of each lateral surface 140 may be the same along the longitudinal axis L direction of the light guide 105. In another embodiment, the lengths of each reflecting facet 135 and the length of each lateral surface 140 may be different and may vary along the longitudinal axis L direction of light guide 105.
In an embodiment, reflecting facets 135 and the lateral surfaces 140 are densely placed at end portions 115a, 115b of light reflecting face 115 when compared to the light reflecting face's middle portion 115c. As a result, a number of light reflective facets 135 are configured to collect a collimated light beam portion at the middle portion 115c in a luminous intensity amount that's less than a collimated light beam portion from a number of reflective facets 135 from end portions 115a and 115b, as from
In an embodiment, the light emitting face side 120 is adapted to receive a collimated light beam 11 from the light reflecting face 115. The collimated light beam 11 directed towards the light emitting face side 120 is angled 90 degrees with respect to the collimated light beam 11 that is received on the plurality of light reflecting facets 135. The light emitting face 120 is provided with a plurality of exit facets 150 along a longitudinal axis L. The plurality of exit faces 150 are angled 90 degrees with respect to the light guide's 105 optical axis OA and may be oriented substantial to 90 degrees. However, the present invention is not limited to facets angled at 90 degrees with respect to the optical axis OA of light guide 105. Furthermore, light emitting face or exit face 120 preferably includes facets formed in a step-wise facet arrangement 200, which may vary from course to fine step dimensions anywhere along the light emitting face 120 as suitably needed for tailoring luminous effects or manufacturing enhancements.
As a result of the above described light guide 105 and coupler 130 configuration, a light distribution width on the light emitting face side 120 is more than compared to the light beam distribution width spread from the light source.
Optical Axis OA
Optical axis OA functions as a reference axis line that defines the principal light path along which light propagates through an optical system along which there is some degree of rotational symmetry.
The term “optical axis” is used herein to refer to an imaginary line or plane that defines a path along which light propagates.
Longitudinal Axis L
Longitudinal axis L functions as a reference axis line that defines the principal light path from a single point light source 1 towards the target point direction along which the light propagates. The longitudinal axis is the direction in which collimated light rays are generally received in the light guide 105.
Operation of the light guide assembly 100 shown in the
In operation, the light rays or the light beam 145 emitted by the light source 1 are collimated by the coupler 130 to generate a collimated light beam 11. The collimated light beam 11 is then transmitted towards the light reflecting face 115 along the longitudinal axis L of the light guide 105. Light reflecting facets 135 are adapted to receive the collimated light beam and directs the collimated light beam 11 towards the light emitting face side or exit face 120 of the light guide 105 via the light-emissive body 125 of light guide 105. In an embodiment, these reflecting facets 135 are angled at substantially 45 degrees such that light rays incident thereon will be totally internally reflected by the light reflecting facets 135 back through the light-emissive body 125 and out of the light guide 105 through the light emitting face side 120 of light guide 105.
As previously discussed, the middle portion 115c of the light reflecting face 115 is configured to receive the collimated light beam and has a luminous intensity value that is higher than a luminous intensity value received on the end portions 115a, 115b of the light reflecting face 115 by the collimated light beam. Thus by receiving collimated light beams of varying luminous intensities at different portions of the light reflecting face 115, the light beam is evenly distributed along the light emitting face side 120 of the light guide 105.
Therefore with the present inventive light guide assembly 105, a light beam that is homogenous or evenly distributed at the curved shaped light guide along the light emitting face or exit face 120 is produced by using the single coupler and the light source.
Although the present disclosure is provided with reference to figures, all of the embodiments shown in figures are intended to explain the preferred embodiments of the present invention by ways of examples, instead of being intended to limit the present invention.
It should be appreciated by those skilled in the art that various changes or modifications may be made in the present disclosure without departing from the principles and spirit of the inventive disclosure, which are intended to be covered by the present invention as long as these changes or modifications fall within the scope defined in the claims and their equivalents.
Any numerical values recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if it is stated that the amount of a component or a value of a process variable such as, for example, temperature, pressure, time and the like is, for example, from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 etc. are expressly enumerated in this specification. For values, which are less than one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 as appropriate. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner.
Unless otherwise stated, all ranges include both endpoints and all numbers between the end points. The use of “about” or “approximately” in connection with a range applies to both ends of the range. Thus, “about 20 to 30” is intended to cover “about 20 to about 30”, inclusive of at least the specified endpoints.
The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all purposes.
The term “consisting essentially” of to describe a combination shall include the elements, ingredients, components or steps identified, and such other elements ingredients, components or steps that do not materially affect the basic and novel characteristics of the combination.
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